1. Technical Field
The present invention relates to the field of remote controlling, and more particularly, to remote controlling over a delayed communication link via a vision display.
2. Discussion of the Related Art
Prior to setting forth the background of the related art, it may be helpful to set forth definitions of certain terms that will be used hereinafter.
The term “remotely piloted aircraft” (RPA) or “unmanned aerial vehicle” (UAV/RPA) as used herein in this application, refers to an aircraft flying without a human pilot. A UAV/RPA may be remotely controlled or fly autonomously based on pre-programmed flight plans or more complex dynamic automation systems. UAVs/RPAs are currently used in a number of military roles, including reconnaissance. They are also used in a small but growing number of civil applications such as firefighting when a human observer would be at risk, police observation of civil disturbances and crime scenes, and reconnaissance support in natural disasters.
The term “payload” as used herein in this application, is the load carried by an UAV/RPA exclusive of what is necessary for its operation. The payload may comprise, inter alia, an imaging apparatus that provides the user of the UAV/RPA with a dynamic vision display (e.g. a video sequence). The vision display may comprise a predefined point that corresponds with the general pointing point of the payload. The pointing point may be indicated in a particular graphic manner (e.g., a cross) so that the user will be informed of the current pointing direction of the payload.
The term “transponder” as used herein in this application, refers to a communication relay unit, usually in the form of a communication satellite that enables long range communication between the user and the remotely controlled UAV/RPA.
FIG. 1 is a high level schematic diagram showing a communication link between a user and a remote controlled unmanned aerial vehicle (UAV/RPA). A user (not shown) is in operative association with a control station 10 that is in direct communication with a transponder such as a communication satellite 20. Communication satellite 20 is in direct communication with UAV/RPA 30 that carries a payload such as an imaging apparatus 35. Between imaging apparatus 35 and a potential target 40 there is a direct line of sight. In operation, imaging apparatus 35 repeatedly captures images that may contain potential target 40. These images are transmitted to communication satellite 20 which in turn, transmits them to control station 10 thereby providing the user with a dynamic vision display (e.g. video sequence) associated with the pointing direction of imaging apparatus 35.
Remote controlling a UAV/RPA via a transponder, as discussed above usually results in a substantial delay in the communication link. The delay is constituted of two parts. The first part is an uplink delay which is the delay from the time a control command is given (and transmitted) by the user until the control command reaches the payload. The second part is a downlink delay which is a delay from the time of a particular image of the video sequence is captured until the time that particular image reaches the user.
Consequently, controlling a payload on a UAV/RPA over a delayed communication link may pose substantial challenges for UAV/RPA users. Many UAV/RPA operations require the payload to be pointed directly at user identified targets seen on the vision display.